This question asks to identify the gas evolved when zinc reacts with sulphuric acid. This is a classic example of a single displacement reaction where a more reactive metal displaces hydrogen from an acid.
\[ \text{Zn} \text{(s)} + \text{H}_2\text{SO}_4 \text{(aq)} \rightarrow \text{ZnSO}_4 \text{(aq)} + \text{H}_2 \text{(g)} \]
Correct Option: D) Hydrogen
This is a logical reasoning problem involving ranking based on weight. We need to deduce the relative weights of the six cars (P, Q, R, S, T, U) from the given statements and identify the heaviest one. We will represent "heavier than" with a greater than symbol (>) to build a chain of inequalities.
B) R — Based on the step-by-step deduction, R is heavier than P, and P is heavier than T, which is heavier than S, which is heavier than Q, which is heavier than U. Thus, R is the heaviest car.
To solve this problem, we need to compare the positions of digits in the original number with their positions after arranging the digits in ascending order from right to left. We will list the original number, then sort its digits, and finally compare the positions.
| Digit | 7 | 6 | 3 | 9 | 4 | 8 | 2 |
|---|---|---|---|---|---|---|---|
| Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Digit (New) | 9 | 8 | 7 | 6 | 4 | 3 | 2 |
|---|---|---|---|---|---|---|---|
| Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Original Digit | 7 | 6 | 3 | 9 | 4 | 8 | 2 |
| New Digit | 9 | 8 | 7 | 6 | 4 | 3 | 2 |
| Unchanged? | No | No | No | No | Yes | No | Yes |
D) Two
The question asks to identify the chemical process where a substance gains hydrogen. We need to recall the definitions of common chemical reactions, specifically oxidation and reduction, in terms of hydrogen transfer.
Correct Option: C) reduction
The question asks about the original number of parts into which the Articles of the Indian Constitution were grouped. This is a factual question related to the structure of the Indian Constitution at its commencement.
Correct Option: A) 22. The Indian Constitution, at the time of its adoption, was divided into 22 Parts, containing 395 Articles and 8 Schedules.
The reactivity of metals is determined by their position in the reactivity series. Metals higher in the series are more reactive, while those lower in the series are less reactive. The question asks for the metal with the least reactivity among the given options.
Correct Option: D) Gold has the least reactivity among the given options. It is a noble metal, known for its resistance to corrosion and oxidation due to its very low reactivity.
Study the given diagram carefully and answer the question. The numbers in different sections indicate the number of persons.
How many such children are there who like music but NOT sports?
To find the number of children who like music but not sports, we need to analyze the Venn diagram sections related to music and exclude those who also like sports.
Therefore, the number of children who like music but not sports is 42.
Correct Option: B) 42
This is a syllogism problem. We will use Venn diagrams to represent the given statements and then check which of the conclusions logically follow from these diagrams.
Correct Option: C) Only conclusion (II) follows.
The heat produced in an electric circuit is proportional to ______.
(current)²
\(\frac{1}{\text{current}}\)
current
\(\frac{1}{(\text{current})^{2}}\)
The question asks about the relationship between the heat produced in an electric circuit and the current flowing through it. This relationship is described by Joule's Law of Heating.
A) (current)\(^2\) — As per Joule's Law of Heating, the heat produced in an electric circuit is directly proportional to the square of the current flowing through it, given constant resistance and time.